A review on Raman finger prints of doping and strain effect in TMDCs

Two-dimensional layered materials such as graphene, h-BN and Transition Metal Dichalcogenide (TMDCs) have attracted much research interest due to their unique physical attributes. In this regard, Raman Spectroscopy is extensively used for characterizing these materials. Here, we have reviewed the effect of doping and uniaxial strain on the electrical and structural properties of TMDC materials. The uniaxial strain is reported to cause redshift and splitting of E-2g (in plane vibrations) mode into two sub bands Ey(g)(+1) and Ey(2g)(-1) in MoS2, W-S(2), WSe2 and MoTe2. On the other hand, the doping of TMDCs affects their A(1g) (out of plane vibrations) mode due to strong electron-phonon interactions; n-type doping causes red-shift while p-type doping assists blue-shift of A 15 mode. Furthermore, an up to date literature survey is carried out in Table( )1, which throws light on the recent developments and trends in this emerging field. This short review provides a new route for further improvements and progresses by modifying the electrical and structural properties of TMDCs.